The rubber polymer of a pneumatic tire is vulcanized by placing a newly constructed tire in a mold and applying heat and pressure to cause the rubber polymer to be vulcanized and assume a desired shape and design by pressing the tire against the mold. Tires are most usually vulcanized with the axis of rotation of the tire extending vertically, such that a tire mold has mating upper and lower portions that form the bead and sidewall regions of the tire, with both the upper and lower mold portions forming a part of the ground engaging tread region of the tire. While smaller tire molds may be used with a clam shell type of vulcanization press, very large tires for farm equipment, earthmoving equipment and similar applications have the upper and lower portions of the tire mold configured as separate units that are assembled with one another by placing a new or retreaded tire in the lower portion of the mold, then mating the upper portion of the mold to the lower portion using a crane or hoist. In such an operation the fixing of the upper and lower mold portions to one another can be very time consuming and labor intensive, which has a negative effects on efficiency and cost of production. The present invention provides an apparatus and method for improving the efficiency and reducing the cost of vulcanization of very large new or retreaded tires.